How to distinguish the advantages and disadvantages of graphite product?

1. Flexural strength of materials

The flexural strength of a material is a direct reflection of material strength, showing the tightness of the internal structure of the material. The material with high strength has relatively good loss resistance. For the electrode with high precision requirements, the material with high strength should be selected as far as possible. For example, TTK-4 can meet the requirements of general electronic connector molds, but for some electronic connector molds with special accuracy requirements, TTK-5 materials with the same particle size but slightly higher strength can be selected. 

2. Shore hardness of materials

In the subconscious understanding of graphite, graphite is generally considered to be a relatively soft material. However, the actual test data and application show that the hardness of graphite is higher than that of metal materials. In the special graphite industry, the general hardness test standard is shore hardness measurement, and its test principle is different from that of metal. Due to the layered structure of graphite, it has very excellent cutting performance in the cutting process. The cutting force is only about 1/3 of that of copper material, and the surface after machining is easy to deal with.

However, due to its high hardness, the loss of cutting tools will be slightly greater than that of metal cutting tools. At the same time, materials with high hardness have excellent control over discharge loss. In our EDM material system, there are two kinds of materials with the same particle size that are widely used, one with slightly higher hardness and the other with slightly lower hardness, so as to meet the needs of customers with different requirements. For example, the average particle size is 5μm, including iso-63 and TTK-50; The average particle size is 4μm, including TTK-4 and TTK-5; The average particle size is 2μm, including TTK-8 and TTK-9. Mainly considering the various types of customers for discharge and machining orientation.

3. Average particle diameter of materials

The average particle diameter of the material directly affects the discharge condition of the material. The smaller the average particle of the material, the more uniform the discharge of the material, the more stable the discharge condition and the better the surface quality.

For forging and die casting molds with low surface and precision requirements, it is usually recommended to use materials with coarse particles; For electronic molds with high surface and precision requirements, it is recommended to use materials with average particle size less than 4μm to ensure the precision and surface finish of the processed molds. The smaller the average particle size of the material, the smaller the loss of the material, the greater the force between each ion group.

At the same time, the larger the particle, the faster the discharge speed, the smaller the loss of rough machining. The main reason is that the current intensity of the discharge process is different, resulting in different discharge energy. However, the surface finish after discharge also changes with the change of particles.

4. Inherent resistivity of materials

According to our statistics on the characteristics of materials, if the average particles of materials are the same, the discharge speed of the material with high resistivity will be slower than that of the material with low resistivity. For materials with the same average particle size, the strength and hardness of materials with low resistivity will be correspondingly slightly lower than those with high resistivity. That is, the discharge speed and loss will be different. Therefore, it is very important to select materials according to the needs of practical application.

Due to the particularity of powder metallurgy, each parameter of each batch material has its representative value and a certain fluctuation range. However, the discharge effect of the same grade of graphite material is very close. The difference of application effect caused by various parameters is very small. The selection of graphite material and electrode material is directly related to the discharge effect. To a large extent, whether the selection of material is appropriate determines the final situation of discharge speed, machining accuracy and surface roughness. Mastering the above points is of great help to us in identifying the grade of graphite materials, to read more graphite materials information contact us.